


Bump goes the heart

by PredictableDisaster



Category: Adventure Time
Genre: F/F
Language: English
Status: Completed
Published: 2020-05-21
Updated: 2020-05-21
Packaged: 2021-03-02 23:33:45
Rating: General Audiences
Warnings: Creator Chose Not To Use Archive Warnings, No Archive Warnings Apply
Chapters: 4
Words: 1,951
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/24305191
Author URL: https://archiveofourown.org/users/PredictableDisaster/pseuds/PredictableDisaster
Summary: A series of prompts that I got over at my tumblr involving Marceline and Bonnibel's heartbeat.
Relationships: Princess Bubblegum/Marceline
Comments: 1
Kudos: 55





	1. Chapter 1

**Author's Note:**

> these prompts started off cute as shit then the last one just hit me in the head
> 
> Prompt:   
> Bubbline prompt: Marceline listening to the beating/pounding of Bonnie's bubblegum heart

“Marcy, what are you doing?”

Marceline hums under her breath and curls a little more into herself.

“Listenin’.” she mumbles.

She could see Bonnibel tilt her head at this. She was by her closet, swapping into something more comfortable to sleep in than her daily wear. She pulls out a shirt and pads her way to Marceline.

She’d been floating in a corner for a while now. Too tired to do much else than exist. Bonnibel offers her the shirt and she quietly accepts it.

“What are you listening to?” Bonnibel asks, curious but mostly just wanting to converse with her. She always knew to fill the silence when Marceline was feeling this way.

Glob, how did she ever survive without this woman.

“You.” She mumbles absentmindedly.

She heard her laugh quietly before realizing what she said. She turns away in embarrassment, busying herself in changing into the offered shirt. “I meant, I was listening to your heartbeat and stuff.”

There was a moment of silence. “What do you mean?” Curiosity coating the question.

“Uh,” she rubs at her bite mark. “If it’s quiet enough and if I focus I can hear your heartbeat and other stuff from several feet away.”

“Huh.”

She turns to see Bonnibel on the bed, face scrunched up in thought. A second later, she pats the free other side of her bed. Marceline floats to her side without a second thought.

When she was close enough, Bonnibel gently grasps her and pulls her down into bed. Placing her head on top of her chest, making sure to position her ear right over her heart.

“Uh, Bon? Not complaining but if I remember right you were pretty much demanding to be little spoon a while ago.” Despite that, she wraps her arms around Bonnibel and settles comfortably against her.

“Shh, I’m giving you front row seats.”

“Uhh, what?”

Bonnibel threads her fingers through her hair, lightly scratching at her scalp. “I just realized why you loved being in this position all those years ago and so I wanted to give this to you since I haven’t held you like this since… yeah.”

“Oh.”

“Mn hmm,” she feels her drop a kiss onto her hair. “Will you be okay just listening to my heartbeat? I can stay up and talk with you if you want.”

She thinks about that.

She could clearly hear Bonnibel’s heart, the strong and steady rhythm lulling her into comfort. It has been so long since she’s had the chance to listen to it this close. Along with the warmth of Bonnibel’s arms around her, this has been the most comfortable she’s been in centuries.

“This is good,” she could feel herself starting to purr. “This is really good.”

She hears her hum. “Cool, goodnight Marcy.”

There were words at the tip of her tongue. She wanted to say them, she really did. But she wasn’t ready to say it, and Bonnibel wasn’t ready to hear it yet. If she said it now, it wouldn’t mean even a fraction of how she felt.

So she just nuzzles in closer, rubbing soft circles onto Bonnibel’s back. Happy having this little comfort back into her life.

“Night, Bonnie.”


	2. Chapter 2

**Summary for the Chapter:**

> Bubbline prompt:  
> PB undergoing a cardiac stress test (running on a treadmill while connected to a heart monitor) and Marceline checking her vitals (likely with her vampiric senses)

As with almost everything with Bonnibel Bubblegum, it turns into an experiment.

Despite all of her apprehensions it’s not like it used to be, several odd centuries ago. Which is nice. There is a light in her eyes that isn’t solely out of hunger for knowledge. She asks for permissions sincerely and talks about boundaries. It doesn’t feel like a clinical dissection anymore.

She’s brought to a personal gym somewhere in the personal area of her castle. It’s a little odd to be there because this used to be where they spared to make sure the princess could handle herself. The armor and weaponry are gone, replaced with treadmills and weights and other similar equipment.

Bonnibel had the test set up and gave Marceline a notebook. She gave her instructions when to take note of her heartbeat. She pauses for a second then asks “Can you monitor my blood pressure?”

“Unless you want my fangs stuck to you the entire time, no.” Marceline answers absently, looking at the monitor. She glances at the scientist, curious about her silence, and sees her trying to fight down a blush.

Cute.

Marceline politely looks away when Bonnibel tells her she’ll be taking off her shirt to do a thing. Honestly she just turned around the moment Bonnibel started fidling with the edge of her shirt and stopped listening. It’s sort of become a sign for them now and it’s actually really nice to have that.

When she’s given the green light to look again, she just waves her hand in dismissal. “Better this way, I won’t see the monitor and stuff.”

Bonnibel gives a short “oh” then informs her she’ll be starting in a bit. The monitor buzzes to life and Marceline tries drown it out focus on the heartbeat.

It’s not as obtrusive a sound as she thought it would be. Focusing on Bonnibel’s heartbeat was such an old skill she hadn’t done that she thought this would be harder than necessary.

Seems that she was wrong as shit because Bonnibel’s heartbeat is soothing her so much she almost doesn’t hear the woman itself ask her to jot down her heart rate.

The test goes on for about seven minutes and Bonnibel is beyond thrilled that she is as -if not more- accurate to the results from the machine.

Bonnibel starts babbling about how she wants to bring her to the hospital during times when there aren’t enough machines and other circumstances to help people out. She muses telling her that a hospital isn’t very quiet and that many heartbeats can and will throw her off.

She saves it for later, she’ll redirect the nerd’s enthusiasm to a different experiment. Hopefully something where she can help.


	3. Chapter 3

**Summary for the Chapter:**

> Bubbline prompt:   
> the cardiac stress test drabble from PB's POV

Learning new things is always a chance to conduct an experiment.

Despite knowing the vampiric demon for centuries, she hadn’t known how sensitive her hearing is. That actually explains some things in their relationship.

Their very tumultuous relationship. Which, right now, is under the classification of friendship.

Yes.

Okay, not thinking about that for now.

She asks Marceline if she’s willing to do the experiment. She explains what she’s going to do, what she wants to know, and how she’s going to do it. The whole time Marceline looked mildly shocked and it took her a few minutes to realize that she wasn’t used to being asked for permission and given explanations before being subjected to an experiment. Right, unethical experimentation on sentient beings was sort of her shtick.

Bonnibel does her best to hide her grimace as she leads Marceline to the exercise room.

The room used to be her personal training area. The vampiric demon thought her self-defense and other skills which had helped her immensely while traversing Ooo. Now the swords and shields were replaced with treadmills and weights.

She gave Marceline a notebook to take note of her heart rate. She explains to Marceline what to do and pauses for a moment before asking if she could also monitor her blood pressure. She should have honestly expected the answer, it was blatantly obvious for Grog’s sake, but she still felt heat rise to her cheeks.

After she had her face under control she addressed Marceline again, fidling with the edge of her shirt absently. “I have to, uh, take off my shirt to put on the electrodes to monitor my heart. It might take a bit so could you- oh okay uh thank you Marcy.” She hadn’t even finished yet and the other woman had already politely turned away.

She goes through the preparations as quickly as she could. After everything was good and her shirt was back on she gave Marceline permission to turn around again. The other woman waves her hand and says, “Better this way, I wont see the monitor and stuff.”

She nods, realizes she can’t see the action and instead mumbles an ‘oh’, then moves to proceed with the stress test.

It was several minutes of watching Marceline float quietly in the room, back towards her. It wasn’t very exciting and she kind of felt bad because this was probably only interesting to her.

When she showed the results to Marceline though, the vampire looked genuinely impressed at how close the results were. The scientist smiled broadly at her and started throwing suggestions on where it would be very useful. In all honesty, she didn’t care about that too much. She just wanted to have a better excuse to hang out with her best friend than wanting to hear her music.

One day she’ll be able to ask her to visit on the grounds of absolutely nothing again. For now, advances hidden as scientific inquiry and altruistic acts would do.


	4. Chapter 4

**Summary for the Chapter:**

> One more Bubbline prompt:  
> the cardiac stress test drabble from the POV of PB's heartbeat

You’ve been steadily beating for 827 years, 5 months, 18 days, 15 hours, 4 minutes, 17 seconds and counting. You gotta say you’ve been doing a pretty good job.

There have been some less steady moments but your host needs those, you know? When she’s busy getting away from threats, you kick in the pedal and give her the much needed boost for her muscles to work properly. Always saves her skin and she starts being thankful about you after she gets her hands on some nifty science books.

Ah, speaking of those nifty science books, she sure has trained you to not do some things too. Like, whenever she’s anxious, you’re supposed to beat more than usual. But noooo she makes you stay normal no matter the circumstances. Kinda annoying but it’s whatever, you’re beating and she’s moving so it doesn’t matter. Also when she’s lying, you’re supposed to change infinitesimally ‘cause of the other chemical stuff that happens around you. But, like before, nah. She just stops that and so you just go steady. Little pink weirdo.

Something she has never caught on, however, is your instability around this demon girl.

When she sees her you skip a beat or two. When they make affectionate gestures towards each other you start going faster. When she sings you stutter to a soft slow rhythm that she may or may not think means you’ve completely stopped.

Whenever she’s around that girl you’re allowed to do whatever you damn well please. Which sucked 'cause Things Happened and for centuries they were apart and you were back under an iron grip.

(Except during very very rare days when she can’t take it and you quietly shatter and pierce her all over and she cries for hours on end. You’d honestly rather stop than painfully squeeze her.)

But, as it goes, more Things Happen and the demon girl is back and you’re free to do whatever again around her. Your host learns she can hear you (that mildly embarrassed your host enough for you to speed up just the tiniest bit) and goes into Science Mode.

She sets up some test you honestly only care about because you’re under scrutiny here so you gotta work just right. It’s really hard to do it however because every time your host looks at the other woman you falter the slightest bit and you damn well know the demon knows because she tilts her head towards you two when it happens.

You really hope your host doesn’t notice this because man, you really like this freedom. And mostly because it’s so fun speeding into oblivion when that demon so much as brushes her hand against her. How your host reacts is the most endearing if not hilarious thing in the world.

**Notes for the Chapter:**

> anyway that last one was so wild i convinced myself to put all of this here


End file.
